Rotary drill



Nov. 1, 1932. J, JOHNSM 1,885,266

ROTARY DRILL Filed April 3, 1951 2 Sheets-Sheet. l

INVENTOR, Jners Jiknso 72,,-

2 BY I 6 3f TORNEY.-,

Nov. 1, 1932. JOHNSON 1,885,266

ROTARY DRILL Filed April 3, 1951 2 Sheets-Sheet 2 INVENTOR, Jners 75/ 272 5072/ TORNEYZ.

Patented Nov. 1, 1932 UNITED STATES.

nannies onNson; or Los m as; CALIFORNIA" f ROTARY DRILL I Application filed. a rn s, 1931. Serial no. 527,379.

This invention relates to drill bits of the type having rotary, spur cutters on their bottom ends.

An object is to provide a practical, substantial and eflicient means for securing the r tary cutters .on the lower end offthe bit body.

More especially, it is anobject to provide a simple and. highly effective pin and key fastening device to retain a trunnion nut in place v V A further object isto provide for the-eco-. nomical construction, interchange and a's-- sembly of the several parts.' 1 if An additionalxobjecta is to provide abit including arotary, spur cutterpresenting a system of hole-bottom,- cutting spurs and also having spurs for cuttingthe side- Wall of the hole; and to provide a set of rotary cute ters in such angular relation as to produce a central conebottom in the'formation ina manner to tend to operate efficiently in the cutting'ofa straight'hole. p '1 Figure 1 is a partial side elevation section axially of the bit.

Figure 2 is aside elevationoffa hub washer element. a Figure 3 is a plan of a hub gasket.

Figure 4is a plan of perforated footstock washer.

and

Figure 5 is a plan. of a cutter'retaining cap.: Figure 6 is a side elevation of abolt holdingkey. Figure 7. is a side elevation of acap holding bolt. I

Figure 8 is 'an elevation of the inner, side face of a foot-st0ck Section, and r' Figure 9 is an outside, face elevation thereof. 3 r Thereamer comprises 'a body including semi-cylindrical sections 2,,and 3 having meeting die-metrical faces 4 andjare secured face to face bycross bolts 5. Thesesections 7 2+3 have a screw pin 4/011 their top end and also have side-Wall cutting reamer out;

ters 6 mounted in respective pockets and turning'on or with spindles 8; the cutters having'longitudinal teeth and the cutters being parallelto the axis of the bit. Addie tional reamer cutters 9, are disposed on axes lying in planes obliquely to. the axis of the bit and countersunk in respective recesses 10 and 11 in opposite sides of the, body sections 23.' The reanier features. are de scribed inmore detailand claimed-in appli cation No.571,252;, filed October 26, 1931.

The reamerbo'dy sections23' have a screw-pin 12 screwing into a bitbody member 13 whichhas a central, threaded bore 14 to receive a pin 15 provided on alower part of the body here called the foot-stock. This preferably: consists of duplicate members 162. 17 having diametrical meeting faces 18, lying in an axialplane of thebit,.secured to; gether by cross bolts- 19. This sectional-footstock has a crowned head 2O seating snugly against thebottom' of the body member 13.

The body of the bit, as'a Whole, c'onsistsof the parts'13,'16 -17. 'i

.To provide desired Watercirc 'ilation to the bottom of the hole, an axial Water passage 21 extends from the top pin 4 to-the bottom edge of the foot-stock 1 617 The foot-stock ;16 17 presents an acute angled downwardly converging Wedge Whose opposite sides are thickened by circular boss surfaces 22 provided with undercut, annular channels 23 and having substantial lateral trunnions324 With bronze or othersuitable metal bushings 25 Whose-bottoms liein the channels 23. In the drawings, one of the duplicate foot-stock sections isshown in side elevation and the other in section on the axis of its trunnion 24. 1 V I Each trunnion 24 carries a rotary, spur cutter26 of suitableor approved'shape of body and arrangementof teeth.

As here shovvmeach cutter 26 presents a truncated, conicalibody turnably fitted on its trunnion bushing 25, whose axis is at such an angle to the axis of the bit that the system of teeth 27, about the cutter 26, produces, on the bottom of the hole, a line of out which will, by rotation of the bit, form a conical, earth formation core.

The basal or outer side of the truncated cutter presents a system of teeth 28 whose ridges or tips have a flat, truncated, conical orbit. The teeth 28 produce a well-bore cut slightly larger in diameter than that of the reamer body elements 23 so that these do not roll on the wall of the well hole.

Each cutter 26 has an inner, annular shoulder-forming flange 29 to bear against the near end of its trunnion 241. A washer 30 is held against the shoulder 29' by a thimble 31 screwed at 32 on a reduced end part 33 of the trunnion 24:, and thereby retains the applied cutter against end play but allows free rotation thereof. I, 1 7

It is highly desirable to provide: means for preventing the accidental unscrewing of the thimbl e 31 and for this purpose the thimble is provided with a non-circular hole 33, Fig. 5, to receive a complementary head 34 of a bolt 35 which extends into an axial hole 36 provided therefor in the foot-stock trunnion 24. The inner end of the bolt 35: has a nick, slot or recess adapted to register witha pin hole in the foot-stock section, a key 38 being insertibleinto the hole 40 and to interlock in the nick 37 of the belt 35 the key 38 having a: head 3-9 screwed i th footstock thus holding the bolt against accidental s disl'odgeinent.

When it is desired to: remove a cutter 26', thekey screw 39 is withdrawn sulficiently'to release the holding bolt 35 and then any simple tool may be applied to the head 34, which, for this purpose, may have a tool socket 3'4! exposed in a lateral recess 33 provided in the cutter retaining thinrble Vhen the cutters 26 are place, the thimbles 31 and the holding bolt heads 34' are sunk within the distal ends of the cutters so as to be protected. Preferably, the bearing facesof the cutters 26 and their bushings 2 5 are protected against undue wear by provision of gaskets 4:1 lying against the shoulders 29 in the cutter bores, and by gaskets or-washers- 42, on the bosses. 22', receiving the inner end faces 25 of the cutters. I v

The Washer 30 is provided with holding pins 30 to engage inthe end of the trunnion part 33 to prevent rotation of the washer the l atterbeing held by pins 42".

It is desirable to= prevent accidental dislodgment of the foot-stock parts from the driving body part 13 and for this purpose a cross-pin 4:4 in the driving body 13 engages a part of the screw pin 15 to lock this against turning;

Since the toe edge of the foot-stock of the bit body is of quite an acute angle, the axial water duct 21 divides into a plurality of smaller ducts 21, Fig. 8, to distribute the desired volume of water without unduly weakening the stock by large ducts. The footstock is preferably made in two like pieces as this greatly facilitates handling and machining these members, though it could be of one piece if desired.

What is claimed is 1. A rotary drill bit having a foot body provided with an outwardly extending trunnion having its outer end reduced and provided with a screw thread, and a peripheral trunnion shoulder between said body and said threaded end, a rotary cutter mounted on said trunnion and having an internal flange presenting a shoulder lapping on the trunnion shoulder, a washer on the reduced endof the: trunnion and lying against said flange, and a. lockable thimble on the trunnion end to retain the cutter in. place. 2'. A rotary drill bit having av foot body provided with an outwardly extending trunnion having a journal portion and having its outer end reduced and provided with a screw thread, and a peripheral trunnion shoulder between said journal portion and said threaded end, a rotary cutter mounted on said journal portion and having an internal flange presenting a shoulder lapping on said shoulder, awasher onthe reduced end of the trunnion lying against said flange, and a lockable thimble on the trunnion end. to retain the cutter in place; the locking means for the thimble including a bolt whose head is non-rotatably seated in the thimble and whose inner end has in one side a key receiving nick, a screw key whose inner end is adapted tolodge in said nick when the key is screwed into a respective opening therefor in said body.

3. A rotary drill bit provided with trunnions, rolling cutters j'ournaled on the'trunnions, screw thimbles on the ends of the trunnions'to hold the cutters thereon against axial movement and having lateral head slots, bolts'interlockedin the thimbles to prevent unscrewing thereof and having heads with sockets aligned with said slots for reception of a pulling tool, and means keying the bolts in place against rotation and extraction.

4. A rotary drill bit provided with trunnions, rolling cutters journaled on the trunnions, screw thimbles on the ends of the trunnions to retain the cutters in place thereon, bolts insertible and interlocked in the thimbles to prevent unscrewing thereof, and means keying the bolts in place; said thimbles having non-circular apertures and the bolts having heads complementary to the apertures, the thimble's and the heads of the bolts having, respectively, aligned lateral holes for insertion of a pulling device for the bolt.

5. A rotary drill bit provided with trunnions, rolling cutters journaled on the trunnions, thimbles screwed on the ends of the trunnions to retain the cutters in placethereon, bolts interlocked in the thimbles to prevent unscrewing thereof, and means keying the bolts in place; said bolts having heads having holes for accommodation of an extracting tool, and the thimbles having pockets complementary to the bolt heads and having lateral recesses aligned With the holes in the bolt heads.

JENERS JOHNSON. 

